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arXiv · 2301.05705

A NOEMA molecular line scan of the Hubble Deep Field North: Improved constraints on the CO luminosity functions and cosmic density of molecular gas

Leindert A. Boogaard·Roberto Decarli·Fabian Walter·Axel Weiss·Gergö Popping·Roberto Neri·Manuel Aravena·Dominik Riechers·Richard S. Ellis·Chris Carilli·Pierre Cox·Jérôme Pety
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Abstract

We present measurements of the CO luminosity functions (LFs) and the evolution of the cosmic molecular gas density out to z~6 based on an 8.5 arcmin^2 spectral scan survey at 3mm of the iconic Hubble Deep Field North (HDF-N) observed with the NOrthern Extended Millimeter Array (NOEMA). We use matched filtering to search for line emission from galaxies and determine their redshift probability distributions exploiting the extensive multi-wavelength data for the HDF-N. We identify the 7 highest-fidelity sources as CO emitters at 1 =5.0. The relatively large area and depth of the NOEMA HDF-N survey extends the existing luminosity functions at 1<z<4 above the knee, yielding a somewhat lower density by 0.15-0.4 dex at the overlap region for the CO(2-1) and CO(3-2) transitions, attributed to cosmic variance. We perform a joint analysis of the CO LFs in the HDF-N and Hubble Ultra Deep Field from ASPECS, finding that they can be well described by a single Schechter function. The evolution of the cosmic molecular gas density from a joint analysis is in good agreement with earlier determinations. This implies that the impact of cosmic field-to-field variance on the measurements is consistent with previous estimates, adding to the challenges for simulations that model galaxies from first principles.

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Leindert A. Boogaard, Roberto Decarli, Fabian Walter, Axel Weiss, Gergö Popping, Roberto Neri, Manuel Aravena, Dominik Riechers, Richard S. Ellis, Chris Carilli, Pierre Cox, Jérôme Pety. 2023-01-13. A NOEMA molecular line scan of the Hubble Deep Field North: Improved constraints on the CO luminosity functions and cosmic density of molecular gas. https://doi.org/10.3847/1538-4357%2Facb4f0

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